Population-centered medical method: A population-centered medical model for public health medicine.

OBJECTIVES: Public health physicians (PHPs) are trained in both medicine and public health, yet practice models in each of these fields incompletely describe their work. A model of practice for public health physicians would better enable training and professional development in the specialty. The objective of this study was to develop an empirically grounded method of the practice of public health medicine by public health physicians. STUDY DESIGN: This was designed as a constructivist grounded theory (CGT) study. Semistructured interviews with 18 public health physicians in Canada were conducted over the course of 1 year. METHODS: Transcribed interviews were coded in three stages (line-by-line, focused, and theoretical). Constant comparison, theoretical sampling, reflective and analytic memos, and team discussion on reflexivity were used to ensure rigor and the proper application of CGT methods. RESULTS: The key finding of this study is the population-centered medical method (POP-CMM), an empirically grounded method of PHP practice. In this model, PHPs bring values, knowledge, and stances to their practice of medicine with populations as patients. They work to diagnose and intervene on public health issues, with a focus on prevention and systems. Essential to this work is knowledge sharing and relationship building between physicians and populations. CONCLUSIONS: POP-CMM represents a method of practice for PHPs. Further exploration of this method in other countries and systems would bring insight into PHP practice globally. The model has important connections to the practice of medicine and presents the possibility of developing a general model of physician practice for a range of patients, from individuals to populations.

A comparison of the characteristics, motivations, preferences and expectations of men donating sperm online or through a sperm bank.

STUDY QUESTION: How do the demographic characteristics, motivations, experiences and expectations of unregulated sperm donors (men donating sperm online through a connection website) compare to sperm donors in the regulated sector (men donating through a registered UK sperm bank)? SUMMARY ANSWER: Online donors were more likely to be older, married and have children of their own than sperm bank donors, were more varied in their preferences and expectations of sperm donation, and had more concerns about being a sperm donor. WHAT IS KNOWN ALREADY: While studies have examined motivations and experiences of both regulated sperm bank, and unregulated online sperm donors, no study has directly compared these two groups of donors. STUDY DESIGN, SIZE, DURATION: An email was sent to the 576 men who were registered sperm donors at the London Sperm Bank, the UK's largest sperm bank regulated by the Human Fertilisation and Embryology Authority (HFEA), who had commenced donation between January 2010 and December 2016, and had consented to be contacted for research. The online survey, which contained multiple choice and open-ended questions, was completed by 168 men over a 7-week period. The responses were compared to those of sperm donors registered on Pride Angel, a large UK-based connection website for donors and recipients of sperm: our research team had already collected these data. In total, 5299 sperm donors were on Pride Angel at time of data capture and 400 men had completed a similar survey. The responses of 70 actual online sperm donors (i.e. those whose sperm had been used to conceive at least one child) were used for comparison with the sperm bank donors. PARTICIPANTS/MATERIALS, SETTING, METHODS: The survey obtained data on the sperm donors' demographic characteristics, motivations, experiences and expectations of sperm donation. Data from sperm bank donors were compared to online donors to examine differences between the two groups. The study compared online and clinic donors who had all been accepted as sperm donors: online donors who had been 'vetted' by recipients and sperm bank donors who had passed the rigorous screening criteria set by the clinic. MAIN RESULTS AND THE ROLE OF CHANCE: A response rate of 29% was obtained from the sperm bank donors. Online donors were significantly older than sperm bank donors (mean ± SD: 38.7 ± 8.4 versus 32.9 ± 6.8 years, respectively) and were more likely to have their own children (p < 0.001 for both characteristics). Both groups rated the motivation 'I want to help others' as very important. Online donors rated 'I don't want to have children myself', 'to have children/procreate' and 'to enable others to enjoy parenting as I have myself' as more important than sperm bank donors, whereas sperm bank donors rated financial payment as more important than online donors, as well as confirmation of own fertility. Most (93.9%) online donors had donated their sperm elsewhere, through other connection sites, fertility clinics, sperm banks or friends and family, compared to only 2.4% of sperm bank donors (p < 0.001). There was a significant difference in how donors viewed their relationship to the child, with online donors much less likely than sperm bank donors to see their relationship as a 'genetic relationship only'. Online donors had more concerns about being a donor (p < 0.001), for example, being concerned about 'legal uncertainty and child financial support' and 'future contact and uncertainty about relationship with donor-conceived child'. LIMITATIONS, REASONS FOR CAUTION: Findings may not be representative of all sperm donors as only one online connection site and one HFEA registered sperm bank were used for recruitment. WIDER IMPLICATIONS OF THE FINDINGS: Despite concern regarding shortages of sperm donors in licensed clinics and unease regarding the growing popularity of unregulated connection websites, this is the first study to directly compare online and sperm bank donors. It highlights the importance of considering ways to incorporate unregulated online sperm donors into the regulated sector. With many online donors well aware of the legal risks they undertake when donating in the unregulated online market, this would both increase the number of sperm donors available at clinics but also provide legal protection and support for donors. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by the Wellcome Trust Grants 104 385/Z/14/Z and 097857/Z/11/Z. The authors have no conflicts of interest.

In vitro selection of miltefosine resistance in promastigotes of Leishmania donovani from Nepal: genomic and metabolomic characterization.

In this study, we followed the genomic, lipidomic and metabolomic changes associated with the selection of miltefosine (MIL) resistance in two clinically derived Leishmania donovani strains with different inherent resistance to antimonial drugs (antimony sensitive strain Sb-S; and antimony resistant Sb-R). MIL-R was easily induced in both strains using the promastigote-stage, but a significant increase in MIL-R in the intracellular amastigote compared to the corresponding wild-type did not occur until promastigotes had adapted to 12.2 µM MIL. A variety of common and strain-specific genetic changes were discovered in MIL-adapted parasites, including deletions at the LdMT transporter gene, single-base mutations and changes in somy. The most obvious lipid changes in MIL-R promastigotes occurred to phosphatidylcholines and lysophosphatidylcholines and results indicate that the Kennedy pathway is involved in MIL resistance. The inherent Sb resistance of the parasite had an impact on the changes that occurred in MIL-R parasites, with more genetic changes occurring in Sb-R compared with Sb-S parasites. Initial interpretation of the changes identified in this study does not support synergies with Sb-R in the mechanisms of MIL resistance, though this requires an enhanced understanding of the parasite's biochemical pathways and how they are genetically regulated to be verified fully.

Acute memory and psychotomimetic effects of cannabis and tobacco both 'joint' and individually: a placebo-controlled trial.

BACKGROUND: Cannabis and tobacco have contrasting cognitive effects. Smoking cannabis with tobacco is prevalent in many countries and although this may well influence cognitive and mental health outcomes, the possibility has rarely been investigated in human experimental psychopharmacological research. METHOD: The individual and interactive effects of cannabis and tobacco were evaluated in 24 non-dependent cannabis and tobacco smokers in a randomized, placebo-controlled, double-blind, 2 (cannabis, placebo) × 2 (tobacco, placebo) crossover design. Verbal memory (prose recall), working memory (WM) performance including maintenance, manipulation and attention (N-back), psychotomimetic, subjective and cardiovascular measures were recorded on each of four sessions. RESULTS: Cannabis alone impaired verbal memory. A priori contrasts indicated that tobacco offset the effects of cannabis on delayed recall. However, this was not supported by linear mixed model analysis. Cannabis load-dependently impaired WM. By contrast, tobacco improved WM across all load levels. The acute psychotomimetic effects and ratings of 'stoned' and 'dizzy' induced by cannabis were not altered by tobacco. Cannabis and tobacco had independent effects on increasing heart rate and interacting effects on increasing diastolic blood pressure. CONCLUSIONS: Relative to placebo, acute cannabis impaired verbal memory and WM. Tobacco enhanced performance on WM, independently of cannabis. Moreover, we found some preliminary evidence that tobacco may offset the effects of cannabis on delayed, but not immediate, verbal recall. In contrast, the psychotomimetic and subjective effects of cannabis were unaffected by tobacco co-administration. By reducing the cognitive impairment from cannabis, tobacco co-administration may perpetuate use despite adverse health consequences.

Absence or presence? Complexities in the donor narratives of single mothers using sperm donation.

STUDY QUESTION: How do single mothers who have conceived a child via anonymous or identity-release sperm donation represent the donor? SUMMARY ANSWER: While the majority of mothers described their anonymous and identity-release donors as symbolically significant to their families, others were more likely to emphasize that their lack of information limited their thoughts about him. WHAT IS KNOWN ALREADY: There is limited understanding of the factors that impact upon how single mothers represent the donor, and whether or not they are determined by specific donor programmes (anonymous or identity-release). STUDY DESIGN, SIZE, DURATION: Qualitative interviews were conducted with 46 women who had treatment at a UK licensed fertility clinic during the years 2003-2009. Twenty mothers (43%) had used an anonymous donor, and 26 (57%) had used an identity-release donor. PARTICIPANTS/MATERIALS, SETTING, METHODS: Among the 46 mothers interviewed, all had at least one child conceived via donor insemination who was between the ages of 4 and 9 years. Mothers were heterosexual and were currently without a live-in and/or long-term partner. Interview data were analysed qualitatively according to the principles of thematic analysis. MAIN RESULTS AND THE ROLE OF CHANCE: Findings indicated marked diversity in single mothers' representations of the donor. Most (n = 27) mothers talked about the donor as symbolically significant to family life and were likely to describe the donor as (i) a gift-giver, (ii) a gene-giver and (iii) a potential partner. Others (n = 16) talked about the donor as (i) unknown, (ii) part of a process and (iii) out of sight and out of mind. There were mothers with anonymous and identity-release donors in each group. Several mothers explained that their feelings about the donor had changed over time. LIMITATIONS, REASONS FOR CAUTION: All mothers conceived at a licensed fertility clinic in the UK. Findings are limited to individuals willing and able to take part in research on donor conception. WIDER IMPLICATIONS OF THE FINDINGS: The study offers greater insight into the factors influencing the donor narratives produced in single-mother families. It has implications for the counselling and treatment of single women seeking fertility treatment with donor gametes in both anonymous and identity-release programmes. Given that the number of clinics offering identity-release programmes worldwide seems to be increasing, the finding that single women may have varying preferences with regard to donor type, and varying interest levels with regard to donor information, is important. It is recommended that clinicians and other fertility clinic staff guard against making assumptions about such preferences and any thoughts and feelings about the donor or donor information on the basis of marital status. STUDY FUNDING/COMPETING INTERESTS: This study was funded by the Wellcome Trust [097857/Z/11/Z]. The authors have no conflicts of interest to declare.

Online sperm donation: a survey of the demographic characteristics, motivations, preferences and experiences of sperm donors on a connection website.

STUDY QUESTION: What are the demographic characteristics, motivations, preferences and experiences of heterosexual, gay and bisexual sperm donors on a connection website (i.e. a website that facilitates direct contact between donors and recipients of gametes)? SUMMARY ANSWER: This demographically diverse group of men was donating for altruistic reasons and perceived the website as providing greater choice over donation arrangements: approximately one third favoured anonymous donation, most of whom were heterosexual, whilst gay and bisexual donors were more likely to be in contact with children conceived with their sperm. WHAT IS KNOWN ALREADY: Despite substantially more sperm donors being registered on connection websites than with clinics, there has been very little research on this population. Current understanding of the impact of sexual orientation on donors' attitudes is also limited. STUDY DESIGN, SIZE, DURATION: An online survey was conducted over 7 weeks with 383 men registered as sperm donors with Pride Angel, a large UK-based connection website for donors and recipients of sperm. PARTICIPANTS/MATERIALS, SETTING, METHODS: The survey obtained data on participants' demographic characteristics and their motivations, preferences and experiences regarding online sperm donation, including attitudes towards contact with offspring. Differences according to participants' sexual orientation were examined. MAIN RESULTS AND THE ROLE OF CHANCE: Most participants (80.4%, 308) were heterosexual, 10.5% (40) were gay and 9.1% (35) were bisexual; ages ranged from 18 to 69 years (median = 36, mean = 37.3, SD = 9.7). A greater proportion of gay and bisexual men desired open-identity donation (P < 0.005) and contact with offspring (P <0.005) than heterosexual men. Approximately one third (28.7%, 110) had donated sperm; 18.3% (70) had conceived at least one child, of whom a minority (25.7%, 18) were currently in contact with the child, comprising significantly more gay and bisexual than heterosexual men (P = 0.001). Heterosexual men were most likely to state a preference for natural insemination, although the large majority (94.3%, 66) of donors who had conceived children had used artificial insemination. LIMITATIONS, REASONS FOR CAUTION: Findings may not be representative of all sperm donors using connection websites because members of only one website participated and participants were, by necessity, a self-selected sample. WIDER IMPLICATIONS OF THE FINDINGS: This is the first comprehensive study of donors who connect with recipients via the internet, including a substantial number who have donated and conceived children. The findings indicate that sexual orientation may influence men's donation preferences and raise policy issues concerning donor recruitment and the incorporation of online sperm donation into clinical practice. STUDY FUNDING/COMPETING INTERESTS: This study was supported by the Wellcome Trust (097857/Z/11/Z). E.T. is the co-founder of Pride Angel; the remaining authors have no conflicts of interest.

Nitrous oxide speeds the reduction of distressing intrusive memories in an experimental model of psychological trauma.

BACKGROUND: Post-traumatic stress disorder (PTSD) involves maladaptive long-term memory formation which underlies involuntary intrusive thoughts about the trauma. Preventing the development of such maladaptive memory is a key aim in preventing the development of PTSD. We examined whether the N-methyl d-aspartate receptor (NMDAR) antagonist gas nitrous oxide (N2O) could reduce the frequency of intrusive memories by inhibiting NMDAR-dependent memory consolidation in a laboratory analogue of psychological trauma. METHOD: Participants were randomized to inhale N2O (N = 25) or medical air (N = 25) after viewing a negatively valenced emotional film clip ('trauma film'). Participants subsequently completed a daily diary assessing frequency of intrusive thoughts relating to the film clip. A week later, participants completed an explicit memory recall task related to the film. RESULTS: Post-encoding N2O sped the reduction in intrusive memory frequency, with a significant reduction by the next day in the N2O group compared to 4 days later in the air group. N2O also interacted with post-film dissociation, producing increased intrusion frequency in those who were highly dissociated at baseline. Sleep length and quality the night after viewing the film did not differ between the groups. CONCLUSION: N2O speeds the reduction of intrusive analogue trauma memory in a time-dependent manner, consistent with sleep-dependent long-term consolidation disruption. Further research with this drug is warranted to determine its potential to inoculate against enduring effects of psychological trauma; however, caution is also urged in dissociated individuals where N2O may aggravate PTSD-like symptomatology.

Salience attribution and its relationship to cannabis-induced psychotic symptoms.

BACKGROUND: Cannabis is a widely used drug associated with increased risk for psychosis. The dopamine hypothesis of psychosis postulates that altered salience processing leads to psychosis. We therefore tested the hypothesis that cannabis users exhibit aberrant salience and explored the relationship between aberrant salience and dopamine synthesis capacity. METHOD: We tested 17 cannabis users and 17 age- and sex-matched non-user controls using the Salience Attribution Test, a probabilistic reward-learning task. Within users, cannabis-induced psychotic symptoms were measured with the Psychotomimetic States Inventory. Dopamine synthesis capacity, indexed as the influx rate constant K i cer , was measured in 10 users and six controls with 3,4-dihydroxy-6-[18F]fluoro-l-phenylalanine positron emission tomography. RESULTS: There was no significant difference in aberrant salience between the groups [F 1,32 = 1.12, p = 0.30 (implicit); F 1,32 = 1.09, p = 0.30 (explicit)]. Within users there was a significant positive relationship between cannabis-induced psychotic symptom severity and explicit aberrant salience scores (r = 0.61, p = 0.04) and there was a significant association between cannabis dependency/abuse status and high implicit aberrant salience scores (F 1,15 = 5.8, p = 0.03). Within controls, implicit aberrant salience was inversely correlated with whole striatal dopamine synthesis capacity (r = -0.91, p = 0.01), whereas this relationship was non-significant within users (difference between correlations: Z = -2.05, p = 0.04). CONCLUSIONS: Aberrant salience is positively associated with cannabis-induced psychotic symptom severity, but is not seen in cannabis users overall. This is consistent with the hypothesis that the link between cannabis use and psychosis involves alterations in salience processing. Longitudinal studies are needed to determine whether these cognitive abnormalities are pre-existing or caused by long-term cannabis use.

'Friendly allies in raising a child': a survey of men and women seeking elective co-parenting arrangements via an online connection website.

STUDY QUESTION: What are the characteristics, motivations and expectations of men and women who search for a co-parent online? SUMMARY ANSWER: Male and female prospective co-parents differed in terms of their motivations, choice of co-parent and expectations of co-parenting, while differences according to sexual orientation were less marked. WHAT IS KNOWN ALREADY: Very few studies have addressed the experiences of elective co-parents, i.e. men and women who are not in a relationship with each other creating and raising a child together. No study has examined the motivations and experiences of those who seek co-parents online. STUDY DESIGN, SIZE AND DURATION: An online survey was completed by 102 participants (61 men, 41 women) who were members of Pride Angel, an online connection website that facilitates contact between people looking for someone with whom to have a child. The survey was live for 7 weeks. PARTICIPANTS/MATERIALS, SETTING, METHODS: Details of the survey were emailed to all members of Pride Angel. The survey obtained data on participants' demographic characteristics, motivations, choice of co-parent and expectations of co-parenting. Data were analysed to examine differences by gender and by sexual orientation within each gender. MAIN RESULTS AND THE ROLE OF CHANCE: Approximately one-third of men and one half of women seeking co-parenting arrangements were heterosexual. The majority (69, 68%) of participants were single, although significantly more gay and bisexual men (15, 36%) and lesbian and bisexual women (11, 55%) had a partner compared with heterosexual men (4, 20%) and heterosexual women (2, 12%), respectively. Overall, the most important motivation for seeking co-parenting arrangements was in order for both biological parents to be involved in the child's upbringing. Co-parents were looking for someone with a good medical history. Most female co-parents expected the child to live with them, whereas male co-parents either wished the child to reside with the mother or to live equally in both households. A higher proportion of gay and bisexual men than heterosexual men wanted daily contact with the child. LIMITATIONS, REASONS FOR CAUTION: Although this study presents data from the largest sample of elective co-parents to date, the main limitations were the low response rate and that only members of one website were approached. The findings may not be representative of all potential elective co-parents. WIDER IMPLICATIONS OF THE FINDINGS: This study provides important insights into the new phenomenon of elective co-parenting. With the increasing use of assisted reproductive technologies and the diversification of family forms, a growing number of people are seeking co-parenting arrangements to have children. While up until now, elective co-parenting has been principally associated with the gay and lesbian community, this study shows that, with the rise of co-parenting websites, increasing numbers of heterosexual men and women are seeking these types of parenting arrangements. This study generates the first findings on the expectations and motivations of those who seek co-parents online and examines whether these differ according to gender and sexual orientation. Future studies are needed to assess the impact of this new form of parenting on all involved, particularly the children. STUDY FUNDING/COMPETING INTERESTS: This study was supported by the Wellcome Trust (097857/Z/11/Z). Erika Tranfield is the co-founder of the website Pride Angel, the remaining authors have no conflicts of interest to declare.

Examining the profile of high-potency cannabis and its association with severity of cannabis dependence.

BACKGROUND: Cannabis use is decreasing in England and Wales, while demand for cannabis treatment in addiction services continues to rise. This could be partly due to an increased availability of high-potency cannabis. METHOD: Adults residing in the UK were questioned about their drug use, including three types of cannabis (high potency: skunk; low potency: other grass, resin). Cannabis types were profiled and examined for possible associations between frequency of use and (i) cannabis dependence, (ii) cannabis-related concerns. RESULTS: Frequent use of high-potency cannabis predicted a greater severity of dependence [days of skunk use per month: b = 0.254, 95% confidence interval (CI) 0.161-0.357, p < 0.001] and this effect became stronger as age decreased (b = -0.006, 95% CI -0.010 to -0.002, p = 0.004). By contrast, use of low-potency cannabis was not associated with dependence (days of other grass use per month: b = 0.020, 95% CI -0.029 to 0.070, p = 0.436; days of resin use per month: b = 0.025, 95% CI -0.019 to 0.067, p = 0.245). Frequency of cannabis use (all types) did not predict severity of cannabis-related concerns. High-potency cannabis was clearly distinct from low-potency varieties by its marked effects on memory and paranoia. It also produced the best high, was preferred, and most available. CONCLUSIONS: High-potency cannabis use is associated with an increased severity of dependence, especially in young people. Its profile is strongly defined by negative effects (memory, paranoia), but also positive characteristics (best high, preferred type), which may be important when considering clinical or public health interventions focusing on cannabis potency.

Effect of multivitamin supplements on weight gain during pregnancy among HIV-negative women in Tanzania.

Multivitamin supplementation has been shown to reduce the risk of low birthweight. This effect could be mediated through gestational weight gain. However, the effect of multivitamin supplementation on weight gain during pregnancy has not been fully studied. The objective of this study was to examine the effects of multivitamins on pregnancy weight gain. We enrolled 8468 HIV-negative women from Dar es Salaam, Tanzania, in a randomised, placebo-controlled trial of multivitamins on birth outcomes. Women were randomly assigned to receive either a daily oral dose of multivitamin tablets or a placebo and were weighed every 4 weeks from enrolment until the last visit before delivery. Intent-to-treat analyses were carried out to examine the effects of multivitamins on pregnancy weight gain. Multivariate linear and binomial regression models with the log-link function were used to examine the association of weight gain during pregnancy to birthweight. The overall total weight gain was 253 g (SE: 69, P: 0.0003) more, while the overall 4 weekly weight gain was 59 g greater (SE: 18, P: 0.005) among women who received multivitamins compared to placebo. Women in the lowest quartile of gestational weight gain had babies with an average birthweight of 3030 g (SD: 524), while women in the highest quartile had babies weighing 3246 g (SD: 486), on average. Prenatal multivitamin supplements increased gestational weight gain, which was a significant predictor of birthweight.

Tobacco smoking in schizophrenia: investigating the role of incentive salience.

BACKGROUND: Smoking is highly prevalent in people diagnosed with schizophrenia, but the reason for this co-morbidity is currently unclear. One possible explanation is that a common abnormality underpins the development of psychosis and independently enhances the incentive motivational properties of drugs and their associated cues. This study aimed to investigate whether incentive salience attribution towards smoking cues, as assessed by attentional bias, is heightened in schizophrenia and associated with delusions and hallucinations. METHOD: Twenty-two smokers diagnosed with schizophrenia and 23 control smokers were assessed for smoking-related attentional bias using a modified Stroop task. Craving, nicotine dependence, smoking behaviour and positive and negative symptoms of schizophrenia were also recorded. RESULTS: Both groups showed similar craving scores and smoking behaviour according to self-report and expired carbon monoxide (CO), although the patient group had higher nicotine dependence scores. Attentional bias, as evidenced by significant interference from smoking-related words on the modified Stroop task, was similar in both groups and correlated with CO levels. Attentional bias was positively related to severity of delusions but not hallucinations or other symptoms in the schizophrenia group. CONCLUSIONS: This study supports the hypothesis that the development of delusions and the incentive motivational aspects of smoking may share a common biological substrate. These findings may offer some explanation for the elevated rates of smoking and other drug use in people with psychotic illness.

Macronutrient and sociodemographic determinants of gestational weight gain among HIV-negative women in Tanzania.

BACKGROUND: The effect of dietary macronutrient composition on the rate of gestational weight gain among women in sub-Saharan Africa is unclear. OBJECTIVE: To examine the effect of macronutrient intake on the rate of gestational weight gain among HIV-negative women in Tanzania. METHODS: The weights of 8,428 women were measured monthly from 12 weeks of gestation to term. Prenatal dietary intake was estimated as the cumulative average of multiple 24-hour dietary recalls. The association between energy intake and percentage of energy from carbohydrate, protein, and total fat and rate of weight gain (grams per month) was estimated from generalized estimating equation models. Macronutrient effects were adjusted for total energy using the nutrient density model and maternal age, maternal height, maternal mid-upper-arm circumference, parity, marital status, maternal occupation, maternal education, household wealth, season, and treatment regimen assignment. Body mass index (BMI) was considered as a confounder and a potential modifier of the effect of macronutrient intake on gestational weight gain. RESULTS: A 6 g/month increase in rate of weight gain was associated with every 100-kcal increment in daily total energy intake (95% CI, 1 to 12; p = .03). Analyses substituting 5% of energy from fat by protein showed that weight gain would decrease by 72 g/month (95% CI, 6 to 140; p = .03); substituting 5% of energy from carbohydrate by protein decreased gain by 70 g/month (95% CI, 15 to 124; p = .01). Baseline BMI did not modify these associations. CONCLUSIONS: Further research on the effects of macronutrient composition on gestational weight gain is needed to inform the design of supplementation programs for women in developing countries.

Content validity of the Rodeo-SCAT.

The purpose of this study was to establish the content validity of the Rodeo SCAT for the sport of rodeo and bull riding. The study design was comprised of expert consensus and content validation. A modified Ebel procedure was employed to content validate the rodeo SCAT. Content validation using this method includes experts agreeing on the importance of each item that comprises the rodeo SCAT. This 3-stage process involved: 1) face validation by a local committee: 2) initial expert consensus measurement via distance; and 3) a face-to-face discussion for items that did not originally achieve 80% consensus of the group. Experts were chosen from the Canadian Professional Rodeo Sport Medicine Team (Canada) and the Justin Sports Medicine Team (USA). 27 out of a total possible 68 items achieved 80% consensus in the second stage. In the third stage, 4 of the 68 items were removed with consensus from the expert group. All remaining items achieved 80% consensus for inclusion. In summary, the rodeo SCAT is content valid and thus, appropriate for use in the sport of rodeo context or environment.

Characterization of DRP2, a novel human dystrophin homologue.

The currently recognised dystrophin protein family comprises the archetype, dystrophin, its close relative, utrophin or dystrophin-related protein (DRP), and a distantly related protein known as the 87K tyrosine kinase substrate. During the course of a phylogenetic study of sequences encoding the characteristic C-terminal domains of dystrophin-related proteins, we identified an unexpected novel class of vertebrate dystrophin-related sequences. We term this class dystrophin-related protein 2 (DRP2), and suggest that utrophin/DRP be renamed DRP1 to simplify future nomenclature. DRP2 is a relatively small protein, encoded in man by a 45 kb gene localized to Xq22. It is expressed principally in the brain and spinal cord, and is similar in overall structure to the Dp116 dystrophin isoform. The discovery of a novel relative of dystrophin substantially broadens the scope for study of this interesting group of proteins and their associated glycoprotein complexes.

Drug cue induced overshadowing: selective disruption of natural reward processing by cigarette cues amongst abstinent but not satiated smokers.

BACKGROUND: Addicts show both reward processing deficits and increased salience attribution to drug cues. However, no study to date has demonstrated that salience attribution to drug cues can directly modulate inferences of reward value to non-drug cues. Associative learning depends on salience: a more salient predictor of an outcome will 'overshadow' a less salient predictor of the same outcome. Similarly, blocking, a demonstration that learning depends on prediction error, can be influenced by the salience of the cues employed. METHOD: This study investigated whether salient drug cues might interact with neutral cues predicting financial reward in an associative learning task indexing blocking and overshadowing in satiated smokers (n=24), abstaining smokers (n=24) and non-smoking controls (n=24). Attentional bias towards drug cues, craving and expired CO were also indexed. RESULTS: Abstaining smokers showed drug cue induced overshadowing, attributing higher reward value to drug cues than to neutral cues that were equally predictive of reward. Overshadowing was positively correlated with expired CO levels, which, in turn, were correlated with craving in abstainers. An automatic attentional bias towards cigarette cues was found in abstainers only. CONCLUSIONS: These findings provide the first evidence that drug cues interact with reward processing in a drug dependent population.

Sub-chronic impact of cannabinoids in street cannabis on cognition, psychotic-like symptoms and psychological well-being.

BACKGROUND: Cannabis varies considerably in levels of its two major constituent cannabinoids - (delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Recently, we found evidence that those who smoked cannabis containing detectable levels of CBD had fewer psychotic-like symptoms than those whose cannabis had no CBD. The present study aimed, first, to replicate those findings and, second, to determine whether protective effects of CBD may extend to other harms of cannabis, such as memory impairment and reduced psychological well-being. METHOD: A total of 120 current cannabis smokers, 66 daily users and 54 recreational users were classified into groups according to whether analysis of their hair revealed the presence or absence of CBD and high versus low levels of THC. All were assessed on measures of psychosis-like symptoms, memory (prose recall; source memory) and depression/anxiety. RESULTS: Lower psychosis-like symptoms were found in those whose hair had CBD compared with those without. However, this was seen only in recreational users, who had higher levels of THC in their hair. Higher THC levels in hair were associated with increased depression and anxiety. Prose recall and source memory were poorer in daily users with high THC levels in hair while recognition memory was better in individuals with CBD present in hair. CONCLUSIONS: CBD attenuates the psychotic-like effects of cannabis over time in recreational users. Higher THC negatively impacts on memory and psychological well-being. These findings raise concerns for the harms stemming from use of varieties such as 'skunk' (sensimillia), which lack any CBD but currently dominate the supply of cannabis in many countries.

Donor insemination: a follow-up study of disclosure decisions, family relationships and child adjustment at adolescence.

The call for greater openness about gamete donation highlights the need to assess the long-term implications of telling donor-conceived children about their origins. This longitudinal study examined the consequences of secrecy versus openness about donor insemination (DI) for family relationships and child adjustment at adolescence. Thirty heterosexual families with an adolescent (aged 10-14 years) conceived by anonymous DI were assessed using standardized measures of parent-child and marital relationships, and parents' and adolescents' psychological wellbeing. Ten (33%) adolescents had been told about their donor conception. The only differences found between disclosed and non-disclosed families concerned parent-child relationships. In particular, whilst disclosure was associated with lower levels of conflict between mothers and sons, adolescents who were aware of their donor origins reported less warm father-child relationships than those who had not been told. This is of interest given that identity issues and a fuller understanding of donor conception are likely to arise at adolescence. However, differences between disclosing and non-disclosing families cannot be directly attributed to parents' disclosure decisions. Overall, these findings suggest that openness about DI does not create significant difficulties for family functioning or child adjustment and that a child's age and sex may be important in assessing the impact of secrecy and disclosure.

Neural transplants in patients with Huntington's disease undergo disease-like neuronal degeneration.

The clinical evaluation of neural transplantation as a potential treatment for Huntington's disease (HD) was initiated in an attempt to replace lost neurons and improve patient outcomes. Two of 3 patients with HD reported here, who underwent neural transplantation containing striatal anlagen in the striatum a decade earlier, have demonstrated marginal and transient clinical benefits. Their brains were evaluated immunohistochemically and with electron microscopy for markers of projection neurons and interneurons, inflammatory cells, abnormal huntingtin protein, and host-derived connectivity. Surviving grafts were identified bilaterally in 2 of the subjects and displayed classic striatal projection neurons and interneurons. Genetic markers of HD were not expressed within the graft. Here we report in patients with HD that (i) graft survival is attenuated long-term; (ii) grafts undergo disease-like neuronal degeneration with a preferential loss of projection neurons in comparison to interneurons; (iii) immunologically unrelated cells degenerate more rapidly than the patient's neurons, particularly the projection neuron subtype; (iv) graft survival is attenuated in the caudate in comparison to the putamen in HD; (v) glutamatergic cortical neurons project to transplanted striatal neurons; and (vi) microglial inflammatory changes in the grafts specifically target the neuronal components of the grafts. These results, when combined, raise uncertainty about this potential therapeutic approach for the treatment of HD. However, these observations provide new opportunities to investigate the underlying mechanisms involved in HD, as well as to explore additional therapeutic paradigms.

The CannTeen study: verbal episodic memory, spatial working memory, and response inhibition in adolescent and adult cannabis users and age-matched controls.

BACKGROUND: Preclinical and human studies suggest that adolescent cannabis use may be associated with worse cognitive outcomes than adult cannabis use. We investigated the associations between chronic cannabis use and cognitive function in adolescent and adult cannabis users and controls. We hypothesised user-status would be negatively associated with cognitive function and this relationship would be stronger in adolescents than adults. METHODS: As part of the 'CannTeen' project, this cross-sectional study assessed cognitive performance in adolescent cannabis users (n = 76; 16-17-year-olds), adolescent controls (n = 63), adult cannabis users (n = 71; 26-29-year-olds) and adult controls (n = 64). Users used cannabis 1-7 days/week. Adolescent and adult cannabis users were matched on cannabis use frequency (4 days/week) and time since last use (2.5 days). Verbal episodic memory (VEM) was assessed using the prose recall task, spatial working memory (SWM) was assessed using the spatial n-back task, and response inhibition was assessed with the stop-signal task. Primary outcome variables were: delayed recall, 3-back discriminability, and stop signal reaction time, respectively. RESULTS: Users had worse VEM than controls (F(1,268) = 7.423, p = 0.007). There were no significant differences between user-groups on SWM or response inhibition. Null differences were supported by Bayesian analyses. No significant interactions between age-group and user-group were found for VEM, SWM, or response inhibition. CONCLUSIONS: Consistent with previous research, there was an association between chronic cannabis use and poorer VEM, but chronic cannabis use was not associated with SWM or response inhibition. We did not find evidence for heightened adolescent vulnerability to cannabis-related cognitive impairment.